From 9e4140329ee9a787d0f96ac2829d618d47f7973f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 4 Feb 2014 17:24:24 +0900 Subject: kbuild: change out-of-tree build This commit changes the working directory where the build process occurs. Before this commit, build process occurred under the source tree for both in-tree and out-of-tree build. That's why we needed to add $(obj) prefix to all generated files in makefiles like follows: $(obj)u-boot.bin: $(obj)u-boot Here, $(obj) is empty for in-tree build, whereas it points to the output directory for out-of-tree build. And our old build system changes the current working directory with "make -C " syntax when descending into the sub-directories. On the other hand, Kbuild uses a different idea to handle out-of-tree build and directory descending. The build process of Kbuild always occurs under the output tree. When "O=dir/to/store/output/files" is given, the build system changes the current working directory to that directory and restarts the make. Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=" syntax for descending into sub-directories. (We can write it like "make $(obj)=" with a shorthand.) This means the current working directory is always the top of the output directory. Signed-off-by: Masahiro Yamada Tested-by: Gerhard Sittig --- examples/api/Makefile | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'examples/api') diff --git a/examples/api/Makefile b/examples/api/Makefile index ee3c487c13..db0bb34afe 100644 --- a/examples/api/Makefile +++ b/examples/api/Makefile @@ -40,23 +40,23 @@ SRCS += $(addprefix $(SRCTREE)/examples/api/,$(COBJ_FILES-y:.o=.c)) SRCS += $(addprefix $(SRCTREE)/examples/api/,$(SOBJ_FILES-y:.o=.S)) # Create a list of object files to be compiled -OBJS += $(addprefix $(obj),$(SOBJ_FILES-y)) -OBJS += $(addprefix $(obj),$(COBJ_FILES-y)) -OBJS += $(addprefix $(obj),$(notdir $(EXT_COBJ_FILES-y))) -OBJS += $(addprefix $(obj),$(notdir $(EXT_SOBJ_FILES-y))) +OBJS += $(addprefix $(obj)/,$(SOBJ_FILES-y)) +OBJS += $(addprefix $(obj)/,$(COBJ_FILES-y)) +OBJS += $(addprefix $(obj)/,$(notdir $(EXT_COBJ_FILES-y))) +OBJS += $(addprefix $(obj)/,$(notdir $(EXT_SOBJ_FILES-y))) ######################################################################### -$(obj)demo: $(OBJS) +$(obj)/demo: $(OBJS) $(LD) --gc-sections -Ttext $(LOAD_ADDR) -o $@ $^ $(PLATFORM_LIBS) -$(obj)demo.bin: $(obj)demo +$(obj)/demo.bin: $(obj)/demo $(OBJCOPY) -O binary $< $@ 2>/dev/null # Rule to build generic library C files -$(addprefix $(obj),$(notdir $(EXT_COBJ_FILES-y))): $(obj)%.o: $(SRCTREE)/lib/%.c +$(addprefix $(obj)/,$(notdir $(EXT_COBJ_FILES-y))): $(obj)/%.o: $(SRCTREE)/lib/%.c $(CC) -g $(CFLAGS) -c -o $@ $< # Rule to build architecture-specific library assembly files -$(addprefix $(obj),$(notdir $(EXT_SOBJ_FILES-y))): $(obj)%.o: $(SRCTREE)/arch/$(ARCH)/lib/%.S +$(addprefix $(obj)/,$(notdir $(EXT_SOBJ_FILES-y))): $(obj)/%.o: $(SRCTREE)/arch/$(ARCH)/lib/%.S $(CC) -g $(CFLAGS) -c -o $@ $< -- cgit